Mr Woodhouse was Immigration Minister at the time. He said the decision was made by an Immigration NZ official.

"That was a shocker, and I announced... that I was so disappointed with the decision that was made by a senior official, that I suspended Immigration NZ's delegated authority to make those decisions until I could be satisfied that they understood that that was a bad a decision," Mr Woodhouse told The AM Show on Thursday, adding that he had no legal way of overturning the call.

"I wanted to get rid of him and I couldn't. Lees-Galloway can get rid of this guy, and he hasn't. It's the completely opposite scenario. The law prevented me once that decision had been made. If new information comes to light or he offends again, then that can come back before Immigration NZ or the minister... I did everything I could."

Michael Woodhouse.
Photo credit: The AM Show

Immigration NZ's decision-making powers were only stripped for about two weeks, NZME reported in May 2017.

Mr Woodhouse is adamant that in the four years he was Immigration Minister, he never granted residency to anyone whose offending matched the scale of Sroubek's. The AM Show host Duncan Garner asked if he'd resign, should a similar case come to light.

"If you can find an equivalent decision where I supported a drug-dealing liar to stay in this country, then I'm happy to hear from you. You find the file, we'll have the conservation."

Mr Woodhouse said he sometimes did grant residency to criminals, but not if they broke one of his three "bottom lines".

"There are criminal offences committed by people who are recently resident in New Zealand, and there is a prerogative to suspend or cancel that. I did do that in cases of relatively minor offending where the person may have come in as a young person, and their ties to the community and their family links are very strong, they have remorse, they have jobs and so on.

"There were three bottom lines for me though - that was serious family violence, sexual offending and drug importation and supply. Those guys were gone, and so should this one."

Sroubek's safety not important?

Mr Woodhouse said Sroubek's safety shouldn't have been an issue in deciding whether he would be deported or not.

"Rather than ask the question of whether New Zealand would be better or worse off by him staying, he asked whether Sroebek would be more or less safe if he left. That's completely the wrong way to look through this."

"I am now taking advice on my options and need to consider the veracity of the new information that has been made available to me," he said on Wednesday.

Mr Woodhouse says Mr Lees-Galloway was under no pressure to make a decision since Sroubek has about another year of prison ahead of him.

"This guy's in jail, he didn't need to rush the decision. He could have asked his officials to go back, interview, talk to Czech officials. We're not talking about a failed state here... They didn't have to hurry it."

Iain Lees-Galloway.
Photo credit: Newshub.

'One of them should go'

National Party leader Simon Bridges has called for Mr Lees-Galloway to resign the immigration portfolio. Mr Woodhouse isn't so sure, saying Mr Lees-Galloway still has time to make things right.

"One of them should go. In fact, probably both of them should go. But let's see how this plays out.

"If the minister has any sort of compassion for this country and leadership, he should immediately rescind his decision and deport him."